I currently have a web game under the GNU General Public License v3.0 open sourced on GitHub. Recently I found out that someone else had forked the repository and is setting up AdSense on their version. They really only just translated the project to Spanish, changed the name, and added a whole lot of content to the main page (to what I can only assume) to get approved for AdSense because of their original content rules.

So that leads me to:

Are they allowed/in the right to monetize a forked version of my project under the GNU General Public License v3.0?

If not, what should I do about it?

  • 18
    It's worth noting that while it's entirely legal to monetize a GPL project, their integration of AdSense may break the GPL, depending on whether the AdSense code they are adding is licensed under a GPL-compatible license.
    – Tin Man
    Commented Aug 19, 2019 at 7:08
  • 2
    @TinMan I don't think this is a problem, else adding AdSense to any open-source CMS like Drupal or Joomla would not be possible. Commented Aug 20, 2019 at 14:33
  • @DmitryGrigoryev It would certainly be possible; whether it would be legal is a different question. Commented Aug 21, 2019 at 0:16
  • @immibis Yes, I thought it was obvious I referred to the legal feasibility, not to the technical one. Commented Aug 21, 2019 at 10:54
  • Because you develop a web game, the difference between GPL and AGPL might be interesting for you. Commented Aug 22, 2019 at 16:21

4 Answers 4


Yes, what is being done on that fork is entirely legal.

However, you are also allowed to take the useful changes (like the translation) and incorporate them in your own fork. Then you can advertise it as the ad-free version that users might like better.

  • 18
    And if the other party is publishing it on Google Play or somewhere else, they must comply with the GPL terms. Commented Aug 19, 2019 at 2:32
  • 5
    IMHO, also note that you are only allowed to back-port changes if you are able to acquire a copy of the fork legally and under the matching GPL license. If they don't stick to the GPL you need to talk with them and if that fails, you need to sue.
    – Adder
    Commented Aug 19, 2019 at 10:21
  • 5
    @Adder: Exactly, you are only entitled to the source code if you also get your hands on a binary. In this case you are likely out of luck by not having chosen the Affero variant of the GPL. Commented Aug 19, 2019 at 15:03
  • 11
    @adder, the OP appears to already have access to the forked code on GitHub. If it under the GPL, the code can be used. If it is not, the forked code is in violation of the GPL license. Commented Aug 19, 2019 at 17:18
  • 2
    @chrylis I don't think it makes sense to release a web game on Google Play. Commented Aug 20, 2019 at 14:40

IANAL, but I believe this is legal within GPLv3.

That is why there exists Affero General Public License (AGPLv3) license. This will force them to share any source code changes if running it on a web server (e.g. if software/scripts not run locally on client).

  • 3
    Please do not push an agenda here. The AGPLv3 contains no change that addresses the OP’s concerns, and the AGPL’s status as OSS licence is… questionable (and questioned, there’s a thread on the OSI list currently).
    – mirabilos
    Commented Aug 19, 2019 at 16:52
  • 1
    @mirabilos source? From what I can find, AGPLv3 is listed as both FSF Free/Libre and OSI Approved[ref]. I don't have any special feeling about AGPL nor do I use it, but I'm just curious.
    – zypA13510
    Commented Aug 22, 2019 at 6:58
  • 2
    @mirabilos Also, from what I read, it does address the OP's concern by forcing the other party to disclose their source (and with their changes). If the OP's goal is to completely forbid others from monetizing his project, "open source" is probably not the way to do it. Or maybe the infamous SSPL? ;)
    – zypA13510
    Commented Aug 22, 2019 at 7:07
  • The AGPL is currently OSI-approved, yes, but there’s still discussion about whether that was actually a good move. And no, it does not address the OP’s concern, because the AGPL does not force disclosure of the source (only to users accessing the software over a network if it’s a network server, but never to the original author). That would not be Open Source according to well-established community standards including Debian’s (and there’s also a related discussion on an OSI mailing list…).
    – mirabilos
    Commented Aug 22, 2019 at 22:21
  • @mirabilos sorry, but that last sentence sounds a lot like FUD. If you have reason to think that community standards, especially Debian's, regard licences which don't force disclosure to the original author as being non-open-source, then please post your evidence, because my understanding is that Debian are strongly opposed to licences that do force such disclosure.
    – MadHatter
    Commented Aug 24, 2019 at 12:02

Adding to other existing answers, if your goal is to completely forbid others to monetize your project (offering the Program as a Service) without disclosing their source, SSPL (Server Side Public License) was created by the MongoDB team specifically for this purpose.


  1. It is relatively new, whether it's enforceable or not is debatable.
  2. Do not call your project "open source". As in the MongoDB case, the idea was rejected by much of the open-source community.
  • 1
    If it is not open source, why do you add it as an answer here? See also: opensource.stackexchange.com/questions/7522/…
    – Brandin
    Commented Aug 22, 2019 at 7:54
  • 1
    @Brandin Because it seems to fit the OP's intention, and I don't see SSPL being off-topic here, even in your linked question.
    – zypA13510
    Commented Aug 22, 2019 at 7:57

Note that while monetizing itself is legal, the project that is based on a GPL software must (obviously) comply with GPL:

  • Any browser-side source code (which is distributed to users) has to be released under the same license

  • All copyright notices (e.g. Copyright (c) 2019 Hunter Parcells) in such files must be preserved, with additional copyright notices in files that have been modified.

  • If the original game had an interactive notice with copyright/attribution statement (e.g. "About" page), that notice should also be preserved / amended as necessary.

  • Any additional terms from section 7 must be observed.

AdSense itself is not a problem. Many CMS are released under GPL (e.g. Drupal), and those are compatible with AdSense.

If your game runs mostly (or entirely) server-side, you're out of luck. There's no requirement for the new authors to release the code (and thus GPL terms do not apply), and if you were to copy their translated text and release a Spanish version of the original game, you'd violate their copyright. Unless, of course, the forked repository is public, so that its content can be considered to be released.

What open-source games often do to keep spin-offs under control is having a separate license for artwork. If that is the case, you can claim copyright violation for images / sounds, if the project in question reuses those.

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